Study of the two-body nonleptonic $B_{c}(2S)$ weak decays with the QCD factorization approach

TL;DR

The paper investigates the weak hadronic two-body decays of the excited B_c(2S) meson, motivated by HL-LHC prospects. It employs the QCD factorization (QCDF) framework to separate short-distance Wilson coefficients from long-distance hadronic matrix elements, using nonperturbative inputs from the Wirbel–Stech– Bauer form-factor model. The results show that decays to final states containing B_s and light mesons, such as B_s pi and B_s rho, can reach branching ratios around 1e-9, while decays into final states with one charmonium are CKM-suppressed and reach only about 1e-12 or smaller. These predictions provide a reference for experimental searches and offer a testbed for QCDF in heavy-heavy hadronic decays at the HL-LHC.

Abstract

Inspired by the promising prospect of the $B_{c}(2S)$ meson at the coming HL-LHC experiments, the nonleptonic $B_{c}(2S)$ meson weak decays induced by both the $b$ and $c$ decays are investigated with the QCD factorization approach. It is found that branching ratios for the color- and CKM-favored $B_{c}(2S)$ ${\to}$ $B_{s}ρ$, $B_{s}π$ decays can reach up to ${\cal O}(10^{-9})$, which might be measurable. The $B_{c}(2S)$ decays into the final states containing one charmonium are highly suppressed by the CKM factors, and have significantly small branching ratios, ${\cal O}(10^{-12})$ and less, which might be outside the future measurement capability. This paper provides a ready reference for the future experimental study on the hadronic $B_{c}(2S)$ weak decays.